Community Interactions And Sucession


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Community Interactions And Sucession

  1. 1. Community Interactions
  2. 2. Community Interactions <ul><li>Powerfully affect an ecosystem </li></ul><ul><li>Include: </li></ul><ul><ul><li>Competition </li></ul></ul><ul><ul><li>Predation </li></ul></ul><ul><ul><li>Symbiosis </li></ul></ul><ul><ul><li>Herbivory </li></ul></ul><ul><ul><li>Disease </li></ul></ul>
  3. 4. Interspecific Competition <ul><li>When organisms of the same or different species attempt to use an ecological resource at the same place and the same time </li></ul><ul><ul><li>Resource  any necessity to life </li></ul></ul><ul><ul><li>Plants and animals compete </li></ul></ul><ul><ul><li>Winner and losers </li></ul></ul><ul><ul><li>Grass hoppers and bison </li></ul></ul><ul><ul><li>Lynx and fox </li></ul></ul>
  4. 5. Rules, rules, rules <ul><li>Fundamental rule in ecology </li></ul><ul><ul><li>Competitive Exclusion Principle </li></ul></ul><ul><ul><ul><li>No two species can occupy the same niche in the same habitat and the same time </li></ul></ul></ul><ul><ul><ul><li>Prevents competition </li></ul></ul></ul><ul><ul><ul><ul><li>Paramecium caudatum and Paramecium aurelia </li></ul></ul></ul></ul><ul><ul><ul><li>Fundamental Niche (potentially occupied) </li></ul></ul></ul><ul><ul><ul><li>Realized Niche (actually occupied) </li></ul></ul></ul><ul><ul><ul><li>P 1160 </li></ul></ul></ul>
  5. 6. How can species coexist in same community? <ul><li>Realized Niche </li></ul><ul><li>Resource portioning </li></ul><ul><ul><li>Differentiation of niches that enables species to coexist </li></ul></ul><ul><ul><li>Different perches </li></ul></ul><ul><li>Character displacement </li></ul><ul><ul><li>Tendency for characteristics to be more divergent in sympatric (geo overlapping) populations of two species that allopatric (geog sep) populations of two species </li></ul></ul><ul><ul><li>Two species with similar niches will make slight changes in body structure and resources they need so they do not compete for resources </li></ul></ul><ul><ul><ul><li>Finches living on island that are usually very similar have different beaks, one for bigger seeds, one for smaller seeds </li></ul></ul></ul>
  6. 12. Predation <ul><li>Interaction where an organism captures and feeds on another organism (+/-) </li></ul><ul><li>Predator </li></ul><ul><ul><li>Organism that does the killing and eating </li></ul></ul><ul><li>Prey </li></ul><ul><ul><li>Organism that is being killed and eaten (victim) </li></ul></ul>
  7. 13. Defenses p. 1162 <ul><li>Cryptic coloration </li></ul><ul><ul><li>Camouflage </li></ul></ul><ul><li>Aposematic coloration </li></ul><ul><ul><li>Warning coloration for organisms with effective chemical defenses </li></ul></ul><ul><li>Batesian mimicry </li></ul><ul><ul><li>Harmless imitates dangerous </li></ul></ul><ul><li>Mullerian mimicry </li></ul><ul><ul><li>2 or more unpalatable have similar appearance </li></ul></ul><ul><ul><li>Cukoo bee and yellow jacket </li></ul></ul><ul><ul><li>Coral snakes and yellow jackets…yellow </li></ul></ul><ul><li>Predators also use mimicry </li></ul><ul><ul><li>Turtle tongue </li></ul></ul>
  8. 19. Herbivory <ul><li>When a herbivore eats plant or algae (+/-) </li></ul><ul><li>Large mammals, small invertebrates (insects), marine organisms (sea urchins, snails, fish) </li></ul><ul><li>Toxic and nontoxic plants </li></ul><ul><ul><li>Chemical sensors </li></ul></ul><ul><ul><li>olfactory </li></ul></ul><ul><li>Specialized teeth and digestive systems </li></ul><ul><li>Plants defenses </li></ul><ul><ul><li>Toxins: tannins, nicotine, strychnine </li></ul></ul><ul><ul><li>Not harmful to humans </li></ul></ul>
  9. 20. Symbiosis <ul><li>Any relationship where two species live closely together </li></ul><ul><li>Symbiosis literally means “living together” </li></ul><ul><li>3 main types </li></ul><ul><ul><li>Parasitism </li></ul></ul><ul><ul><li>Mutualism </li></ul></ul><ul><ul><li>commensalism </li></ul></ul>
  10. 21. What type of relationship is this? <ul><li>Who is helping who? </li></ul>
  11. 22. Mutualism <ul><li>Both species benefit from the relationship (+/+) </li></ul><ul><li>A Happy couple </li></ul><ul><li>Flowers and bees </li></ul><ul><ul><li>Flowers need bees for pollination, bees need flowers nectar </li></ul></ul>
  12. 24. Commensalism <ul><li>One member of the relationship benefits while the other is neither harmed nor helped (+/0) </li></ul><ul><li>One-sided </li></ul><ul><li>Food or shelter </li></ul><ul><li>Barnacles on whale </li></ul>
  13. 26. What type of relation ship is going on here? <ul><li>Who is helping who? </li></ul>
  14. 28. What type of interaction is going on here?
  15. 29. Parasitism <ul><li>One organism lives on or inside another organism and harms it (+/-) </li></ul><ul><ul><li>Endoparasitism </li></ul></ul><ul><ul><li>Ectoparasitim </li></ul></ul><ul><ul><li>Parasitoidism </li></ul></ul><ul><li>Usually large and multicellular </li></ul><ul><li>Parasite obtains all or part of its nutrients from the other organism </li></ul><ul><li>Host </li></ul><ul><ul><li>Organism that is harmed in relation ship; the one that provides the nutrients to the parasite </li></ul></ul><ul><li>Parasite </li></ul><ul><ul><li>Organism that gets its nutrients from the host </li></ul></ul><ul><li>Do they want to kill their host? </li></ul><ul><ul><li>No, because they need them…mostly annoying </li></ul></ul>
  16. 33. Disease <ul><li>Disease causing agents (+/-) </li></ul><ul><li>Bacteria, viruses, protists, sometimes fungi and prions </li></ul><ul><li>Most are microscopic </li></ul><ul><li>Inflict harm on host </li></ul><ul><li>Not many studies, but they do have an ecological impact </li></ul><ul><ul><li>Sudden oak death: Phytophthora ramorum </li></ul></ul><ul><ul><ul><li>1994-2004 </li></ul></ul></ul><ul><ul><ul><li>Fungus-like protist </li></ul></ul></ul><ul><ul><ul><li>killed thousands of oak trees from CA to Oregon </li></ul></ul></ul><ul><ul><li>West Nile virus </li></ul></ul><ul><ul><ul><li>1999-2003 </li></ul></ul></ul><ul><ul><ul><li>Killed thousands of birds in US as it spread </li></ul></ul></ul>
  17. 35. Recap <ul><li>What are the three types of interactions in a community? </li></ul><ul><ul><li>Competition </li></ul></ul><ul><ul><li>Predation </li></ul></ul><ul><ul><li>Herbivory </li></ul></ul><ul><ul><li>Disease </li></ul></ul><ul><ul><li>Symbiosis </li></ul></ul><ul><ul><ul><li>What types do we have? </li></ul></ul></ul><ul><ul><ul><ul><li>Mutualism </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Commensalism </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Parasitism </li></ul></ul></ul></ul>
  18. 36. Interspecific Interactions and Adaptation <ul><li>Coevolution </li></ul><ul><ul><li>Reciprocal evolutionary adaptations of 2 interacting species </li></ul></ul><ul><ul><li>Genetic change in one sp. influences genetic change in another sp. </li></ul></ul><ul><ul><ul><li>Ex. Gene-for-gene recognition in plant and pathogen </li></ul></ul></ul><ul><ul><li>Aposematic coloration and predators reactions NOT coevolution </li></ul></ul><ul><ul><ul><li>Across multiple species, not 2 linked population </li></ul></ul></ul><ul><li>Current hypothesis is that Predation and competition are key factors that control community structure and drive community dynamics </li></ul><ul><ul><li>Base on temperate and not tropical communities </li></ul></ul><ul><li>Hypothesis is being challenged </li></ul>
  19. 37. Species Diversity <ul><li>Variety of different organisms in a community…dependent on both: </li></ul><ul><ul><li>Species richness </li></ul></ul><ul><ul><ul><li>Total # of diff. sp in comm. </li></ul></ul></ul><ul><ul><li>Relative abundance </li></ul></ul><ul><ul><ul><li>Portion each sp represent of the total individuals in comm. </li></ul></ul></ul><ul><li>Example </li></ul><ul><ul><li>Forest 1 and forest 2, 100 individual </li></ul></ul><ul><ul><li>Forest 1 </li></ul></ul><ul><ul><ul><li>Tree A 25% </li></ul></ul></ul><ul><ul><ul><li>Tree B 25% </li></ul></ul></ul><ul><ul><ul><li>Tree C 25% </li></ul></ul></ul><ul><ul><ul><li>Tree D 25% </li></ul></ul></ul><ul><ul><li>Forest 2 </li></ul></ul><ul><ul><ul><li>Tree A 80% </li></ul></ul></ul><ul><ul><ul><li>Tree B 5% </li></ul></ul></ul><ul><ul><ul><li>Tree C 5% </li></ul></ul></ul><ul><ul><ul><li>Tree D 10% </li></ul></ul></ul><ul><ul><ul><li>Forest 1 is more diverse, even thought both contain 4 types of trees… </li></ul></ul></ul>
  20. 38. Limits on Food Webs <ul><li>Charles Elton 1920 Oxford Biologist </li></ul><ul><ul><li>Food chains are not isolated units but linked in food web </li></ul></ul><ul><li>Each food chain in food web is only a few links long…most hardly more than 5 links from any producer to top-level consumer </li></ul>
  21. 39. Why are they short? <ul><li>2 hypotheses </li></ul><ul><ul><li>Energetic Hypothesis </li></ul></ul><ul><ul><ul><li>Food chain limited by inefficiency of energy transfer along chain (10%) </li></ul></ul></ul><ul><ul><ul><li>Longer in habitats of high photosynthetic productivity </li></ul></ul></ul><ul><ul><li>Dynamic Stability Hypothesis </li></ul></ul><ul><ul><ul><li>Long chains less stable than short ones </li></ul></ul></ul><ul><ul><ul><ul><li>Longer chains have harder time recovering from setbacks like harsh winter, especially at the higher-level </li></ul></ul></ul></ul><ul><ul><ul><li>Shorter chains in unpredictable environments </li></ul></ul></ul><ul><li>Another possibility for short food chains </li></ul><ul><ul><li>Animals tend to be larger at successive trophic levels (except parasites) </li></ul></ul><ul><ul><li>Size of animal and feeding mechanism put limit on food it can put in its mouth </li></ul></ul><ul><ul><li>Mostly, large carnivores cannot live on small organisms because they cannot get sufficent energy from them </li></ul></ul><ul><ul><ul><li>Exception is baleen whales </li></ul></ul></ul>
  22. 40. Important Types of Species <ul><li>Dominant species </li></ul><ul><ul><li>Most abundant or highest biomass </li></ul></ul><ul><ul><li>Powerful control over occurrence and distribution of other species </li></ul></ul><ul><ul><ul><li>Ex, sugar maple in North American forest: so big and abundant that affects shade and soil, therefore, influence what o other species can be in forest </li></ul></ul></ul><ul><ul><li>Why? </li></ul></ul><ul><ul><ul><li>Hypothesis: dominant sp are most competitive at exploiting resources </li></ul></ul></ul><ul><ul><ul><li>Hypothesis: dominant sp. Best at avoiding predation and disease </li></ul></ul></ul><ul><ul><ul><ul><li>Explains success of invasive species </li></ul></ul></ul></ul><ul><ul><li>Removal of dominant species has impact on community </li></ul></ul><ul><li>Keystone species </li></ul><ul><ul><li>Discovered by ecologist Robert Paine of U of Washington </li></ul></ul><ul><ul><li>Not really abundant, but rather have strong control on community structure because their pivotal ecological roles, or niches </li></ul></ul><ul><ul><li>Identify with removal experiments </li></ul></ul><ul><ul><li>Sea star and mussels  remove sea star and decrease species diversity b/c mussels take over space </li></ul></ul><ul><ul><li>Sea otter and sea urchins  remove sea otter, sea urchins eat all the kelp and destroy kelp forest </li></ul></ul><ul><li>Ecosystem engineers (foundation species) </li></ul><ul><ul><li>Cause physical changes to environment that affect structure of community </li></ul></ul><ul><ul><li>Alter through behavior or large biomass </li></ul></ul><ul><ul><li>Foundation species are FACILITATORS that have positive effects on the survival and reproduction of other species </li></ul></ul><ul><ul><ul><li>Beavers change areas of forest into flooded wetlans </li></ul></ul></ul><ul><ul><ul><li>Certain trees provide shade that enable salt marshes to floursih </li></ul></ul></ul>
  23. 41. Ecological Succession <ul><li>Do all ecosystems stay the same all the time? </li></ul><ul><li>What are some things that cause changes to ecosystems? </li></ul><ul><ul><li>Natural and unnatural </li></ul></ul><ul><ul><li>Quickly and slowly </li></ul></ul>
  24. 42. <ul><li>Ecosystems are constantly changing in response to human and natural disturbances. </li></ul><ul><li>As an ecosystem changes, older habitants die out and new organisms move in, causing more change </li></ul>
  25. 43. Ecological Succession <ul><li>Series of predictable changes that occur in a community over time </li></ul><ul><ul><li>Physical environment </li></ul></ul><ul><ul><li>Natural disturbance </li></ul></ul><ul><ul><li>Human disturbance </li></ul></ul>
  26. 44. Intermediate Disturbance Hypothesis <ul><li>Moderate levels of disturbance can create conditions that foster greater species diversity than low or high levels of disturbance </li></ul><ul><ul><li>High levels  wipe out species that are intolerable </li></ul></ul><ul><ul><li>Low level  enable dominant species to take over </li></ul></ul>
  27. 45. Primary Succession <ul><li>Succession on land that occurs on surfaces where no soil exists </li></ul><ul><li>Volcanic eruptions </li></ul><ul><li>Glaciers melting leveling moraine (bare rock) </li></ul>
  28. 48. Stages of Primary Succession <ul><li>Start with no soil, just ash and rock </li></ul><ul><li>First species to populate this area </li></ul><ul><ul><li>“ pioneer species” </li></ul></ul><ul><ul><li>For example, pioneer species on volcanic rock are lichens (LY-kunz) </li></ul></ul><ul><ul><ul><li>Lichens  made up of fungus and algae that can grow on bare rock </li></ul></ul></ul><ul><ul><ul><li>When lichens die, they for organic material that becomes soil…now plants can grow </li></ul></ul></ul>
  29. 49. Secondary Succession <ul><li>Succession following a disturbance that destroys a community without destroying the soil </li></ul><ul><li>Natural </li></ul><ul><ul><li>hurricane </li></ul></ul><ul><ul><li>fires </li></ul></ul><ul><li>Human disturbances </li></ul><ul><ul><li>Farming </li></ul></ul><ul><ul><li>Forest clearing </li></ul></ul>
  30. 55. Succession in Marine Ecosystems <ul><li>Deep and dark </li></ul><ul><li>Can succession happen? </li></ul><ul><li>1987 dead whale off of California </li></ul><ul><ul><li>Unique community of organisms living in remains </li></ul></ul><ul><ul><li>Represents stage in succession in an otherwise stable, deep-sea ecosystem </li></ul></ul><ul><ul><li>Whale-fall community </li></ul></ul>
  31. 57. Whale-Fall Succession <ul><li>Begins when large whale dies </li></ul><ul><ul><li>Sinks to barren ocean floor </li></ul></ul><ul><ul><li>Scavengers and decomposers flock to carcass , our first community </li></ul></ul><ul><ul><ul><li>Amphipods </li></ul></ul></ul><ul><ul><ul><li>Hagfish </li></ul></ul></ul><ul><ul><ul><li>sharks </li></ul></ul></ul><ul><li>After a year, most tissues have been eaten </li></ul><ul><ul><li>Now, second small community of organisms live here </li></ul></ul><ul><ul><li>Body is decomposing, releasing nutrients into the water </li></ul></ul><ul><ul><ul><li>Small fishes </li></ul></ul></ul><ul><ul><ul><li>Crabs </li></ul></ul></ul><ul><ul><ul><li>Snails </li></ul></ul></ul><ul><ul><ul><li>worms </li></ul></ul></ul><ul><li>Only skeleton remains… </li></ul><ul><ul><li>Third community moves in </li></ul></ul><ul><ul><ul><li>Heterotrophic bacteria </li></ul></ul></ul><ul><ul><ul><li>Decompose oil in bones  release of chemical compounds </li></ul></ul></ul><ul><ul><ul><li>Who uses these chemical compounds? </li></ul></ul></ul><ul><ul><ul><ul><li>Chemoosynthetic autotrophs </li></ul></ul></ul></ul><ul><ul><ul><li>In come the crabs, clams, and worms that feed on this bacteria </li></ul></ul></ul>
  32. 58. Teacher, Study Chemical reactions, enzymes, and Chapters 3 and 4